Beidou, China’s GPS equivalent, is operational

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In case you didn’t know it, the Global Positioning System (GPS) is a service of the US government. The government makes it accessible to anyone, but at the end of the day it’s their toy and they can do what they want with the former military project. That might not be an issue for you when you are trying to figure out the fastest way to get to Aunt Mildred’s house, but if you were a leader in China, Russia, India, or the European Union it might be cause for concern. For this reason other countries (and in the case of the EU, groups of countries) are building their own satellite-based navigation systems. China’s, which is known as COMPASS or Beidou, has recently become operational.

Beidou, which translates to “Big Dipper”, will cover the southern Asia for the time being, but will expand outward to be a worldwide navigation system by 2020. At this point it’s composed of 10 satellites, out of a planned total of 35. For reference, the US’ GPS is an array of 32 satellites (at least 24 of which are always operational). At a given time a connection with four satellites is necessary in order to get accurate location data, and more satellites means benefits like better worldwide coverage and faster signal acquisition. The Russian equivalent, GLONASS, has 24 satellites.

Work on Beidou began in 2000, which is quite late compared to the US, but development is happening quickly right now. By the end of 2012 China plans to have six more satellites in the array, bring the total up to 16. The current system, according to a BBC report, is accurate to 10m, which is rather poor compared to that of the US, but it should improve as the number of satellites grows.

Beidou will be tested by the Chinese military who will apparently be able to get more accurate location data from the system. This is not unlike the US’ own Selective Availability program, which degraded location data for non-Department of Defense usage. Selective Availability was turned off in 2000 though, giving all GPS users full accuracy (generally considered to be 3-5m).

Beidou is said to be compatible with other navigation systems. So the same way that the iPhone 4S and other smartphones can work with Russia’s GLONASS in addition to GPS devices might one day be able to work with Beidou, though it will take some time before this is possible.